A Data-Over-Cable Service Interface Specification (DOCSIS) system, for example, can be used to deliver high-definition digital entertainment and telecommunications such as video, voice, and high-speed Internet to subscribers over an existing cable television network. The cable television network can take the form of an all-coax, all-fiber, or hybrid fiber/coax (HFC) network. A multiple service operator (MSO) can deliver these services to subscribers by using a cable modem termination system (CMTS) located at a headed and customer premise equipment (CPE) devices located at subscriber premises. The CPE devices can include cable modems (CMs) or embedded multimedia terminal adapters (eMTAs). A CMTS routes traffic (e.g., data, video, and voice signals) to and from CPE devices on downstream and upstream channels, respectively.
A service flow generally refers to the unidirectional transport of packets including one or more common packet header attributes specified by a classifier and with quality of service (QoS) traffic parameters (e.g., bandwidth, latency, jitter, throughput speed, etc.). Upstream and downstream service flows can be subject to admission control. That is, control mechanisms may exist in the CMTS, for example, to determine whether upstream or downstream traffic can enter the network via service flows to deliver a service. For example, if a client wishes to use network resources for a service, the client may have to first request to use the network resources prior to being permitted to use the network resources to transmit traffic upstream. When the CMTS receives a request to use the network resources, the CMTS can determine whether the network resources exist for the requested services. If the CMTS determines that the network resources are available for the requested service, it can permit the client to use the requested network resources. Conversely, if the CMTS determines that the network resources for the requested service do not exist, then the CMTS can deny access to the network resources.
Alternatively, if the CMTS determines that access to a requested service is part of a subscription plan associated with the requesting client, the CMTS can permit the client to use the requested network resource(s). If the CMTS determines that access to the requested service is not part of a subscription plan associated with the requesting client, the CMTS can deny use of the requested network resource(s).
By providing admission control, the system can control network congestion by denying access to the network during periods of scarce resources. Admission control thereby helps reduce the chances that a new service flow can cause network congestion. Network congestion can result in service degradation for one or more service flows on the network as they contend for resources. For example, for voice traffic, if the network becomes congested, voice traffic packets may be dropped or delayed for any calls on the network thereby resulting in service degradation for all calls.
Admission control processes are typically complex and require detailed information about the service flow being added, information about the existing flows, and information about the system, for example, prior to making an admission control decision.
This disclosure generally describes an admission control process for network resources, such as the cable network resources in a DOCSIS-based system, for example. However, this disclosure is not limited to a cable network or DOCSIS-based system.